An Associated Press style memo indicates a failure to understand that the same-sex marriage fight has been about achieving equal dignity.

Last week, the leak of an internal memo revealed that the Associated Press advised its writers "generally" to call legally married gay spouses "partner" instead of "husband" or "wife."

NOTE TO READERS: Since this Op-Ed article was posted on February 21, the Associated Press changed its ruling on the use of "husband" and "wife." Find an updated version of Nathaniel Frank’s article here.

The massive news agency, which sets the standard for many journalists worldwide, has it wrong; the default should be just what it is for straight married couples: "husband" and "wife." There's simply no rationale to use two different standards for gay and straight people who are legally married in their state.

AP has offered a wholly unsatisfying explanation for the usage distinction. Spokesman Paul Colford wrote last week that "husband" or "wife" "may be used in AP content if those involved have regularly used those terms." Reached this week, he told me, "I expect we will have more to say on the subject before long. We're listening and soliciting views."

While AP has provided no clear rationale for its decision, presumably it believes that because same-sex marriage remains nationally contested, it is acceptable to call legally married gay spouses "partners." Yet marriage is almost always governed at the state level.

True, the Defense of Marriage Act, passed by Congress in 1996, says the federal government does not recognize same-sex marriages. But no one seriously thinks that DOMA "unmarries" gay spouses; it simply denies them federal benefits. What's more, the Justice Department, along with numerous legal experts, believe DOMA is unconstitutional, and the Supreme Court may shortly declare it so. At a minimum, AP's decision not to automatically use "husband" or "wife" for gay spouses in states where same-sex marriage is legal creates the perception that it is taking sides — and the losing side — in a culture war issue.

Nine states plus the District of Columbia allow same-sex marriage. AP's explanation suggests that it allows writers to use "husband" and "wife" if the parties involved make it clear that they use the terms, as though the editors are simply letting their subjects decide. But AP reporters probably don't ask straight couples if they "regularly" use the terms; the agency, like the rest of the world, just employs the words without a second thought.

The point is, those who get married have already decided about terminology. They have chosen to become a husband or wife, and that's what they deserve to be called. Failing to recognize this means failing to recognize what the gay marriage battle has been about: achieving equal dignity by accessing the same institutions and occupying the same symbolic spaces as everyone else.

Being "married" is, after all, a collective identity, in the same way "citizen" is. Both terms connote certain responsibilities, obligations and protections, as well as a sense of dignity and belonging for which there is no substitute. They confer equality on all those who occupy them. Using such a term fairly matters in the same way the front of the bus mattered to those banned from sitting there for no other reason than to designate them as second-class citizens.

Though AP's decision has not pleased gay advocates, it shouldn't please opponents of same-sex marriage either. By suggesting that marriage is defined however each couple says it is, AP undercuts the power of the shared cultural definition of marriage, exactly what conservative opponents of same-sex marriage fear. It casts marriage as a subjective entity that could lose its power to delineate and help enforce our obligations to one another, a crucial part of its modern purpose.

Marriage used to function to regulate property (which included the women who were getting married), encourage and govern procreation and preserve religious and racial lines. But marriage today is far more about celebrating and enforcing people's commitments to care for one another.

While many still cite procreation as the "reason" for marriage, law and society haven't treated it that way for decades, as evidenced by granting marriage rights to those who don't, can't or won't procreate. The power of the word "husband" or "wife" is that it can help guide people's behavior during moments of weakness. Today, marriage is about personal responsibility, a cause conservatives ought to embrace.

If marriage matters at all, it should remain something that, despite its ever-evolving nature, also creates a collective identity with broadly embraced parameters. Yes, many Americans still want it defined to keep gay couples out. But with numerous polls showing majority support nationally for same-sex marriage, those Americans are losing the debate.

Equally important, the states that have legalized same-sex marriage have made their decision to make the one and only "marriage" — not some watered-down, back-of-the-bus version called "civil unions" — available to gay couples. And the individuals who have chosen to marry have made their decision to become husbands and wives. AP's job is to reflect this reality without hesitation. Anything else is editorializing.

Nathaniel Frank is visiting scholar at Columbia's Center for Gender and Sexuality Law.